arb/zeta/ui_vec.c

/*=============================================================================

    This file is part of ARB.

    ARB is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    ARB is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with ARB; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

=============================================================================*/
/******************************************************************************

    Copyright (C) 2012, 2013 Fredrik Johansson

******************************************************************************/

#include "zeta.h"

void
zeta_ui_vec(fmprb_ptr x, ulong start, long num, long prec)
{
    long i, num_odd, num_even, start_odd;
    fmprb_ptr tmp;

    num_odd = num / 2 + (start & num & 1);
    num_even = num - num_odd;

    start_odd = start % 2;

    zeta_ui_vec_even(x, start + start_odd, num_even, prec);
    zeta_ui_vec_odd(x + num_even, start + !start_odd, num_odd, prec);

    /* interleave */
    tmp = flint_malloc(sizeof(fmprb_struct) * num);
    for (i = 0; i < num_even; i++) tmp[i] = x[i];
    for (i = 0; i < num_odd; i++) tmp[num_even + i] = x[num_even + i];
    for (i = 0; i < num_even; i++) x[start_odd + 2  * i] = tmp[i];
    for (i = 0; i < num_odd; i++) x[!start_odd + 2  * i] = tmp[num_even + i];
    flint_free(tmp);
}